Is drop frame causing gradual async ?

All my movies are ntsc. i have had in the past a few that become async gradually. I use dvd2avi, bitrate viewer, cce, pulldown, and maestro. Once in a while i get a movie that starts to gradually become out of sync. Trilight mentions its due to the drop frame. My question is how to know that i need correct for it in cce. I dont recall any of these movies showing drop in bitrate viewer.

Come on guys, i know i am not the only person with async issues 

Well, after doing some more searching...what trilight says makes sense. Still have 2 questions. One is what am i using to tell me that its drop frame? Second? Do i correct for it in my avs script to cce or do i fix the drop frame in pulldown?

If it's NTSC, your assets should always be drop-frame. Make sure all your assets are the same. Your problem occurs when one asset is drop-frame and the other is not. You set the drop-frame flag using pulldown.exe (or even easier with DoItFast4U!) just as is listed in the guides.

Bitrate Viewer doesn't report drop frame status. I believe (and I am recalling this from memory) that VOBEDIT will give this information in the right hand window (header info). Look for DROP_FRAME with a value of "1" for drop frame. I use the GUI for pulldown.exe - once the options are set, they usually don't change. Get it at GUIGUY.WMINDS.COM.

ok, i guess thats what i have been doing wrong...i usually just do pulldown xxx.m2v instead of doing the pulldown blah blah blah drop_frame.. and i will also ck my movie with vobedit thanks ben